Adjustable implant system

ABSTRACT

Systems and methods treat a heart valve using a magnetically adjustable annuloplasty ring attached to or near a cardiac valve annulus. A changing magnetic field may be used to selectively increase or decrease a circumference of, or otherwise modify the shape of, the implanted annuloplasty ring. The adjustable annuloplasty ring includes a tubular body member, one or more adjustable members, and an internal magnet within the tubular body member. The tubular body member and the one or more adjustable members form a ring shape. The internal magnet is configured to rotate in response to a rotating external magnetic field. The internal magnet is coupled to the one or more adjustable members to change a dimension of the ring shape as the internal magnet rotates. A system for treating a heart valve may include an external adjustment device having one or more external magnets to generate the rotating external magnetic field.

RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. §120 of U.S.application Ser. No. 12/411,107 filed on Mar. 25, 2009 and under 35U.S.C. §119(e) of U.S. Provisional Patent Application No. 61/039,349,filed Mar. 25, 2008, and U.S. Provisional Patent Application No.61/093,788, filed Sep. 3, 2008, both all of which are herebyincorporated by reference herein in their entirety.

TECHNICAL FIELD

This application is related to annuloplasty rings. More specifically,this application is related to reversibly adjustable annuloplasty rings.

BACKGROUND

Heart disease and its associated health issues are a large concerntoday. Mitral valve defects such as regurgitation are often caused by adilation of the tissue surrounding the valve. This causes the mitralopening to enlarge, which prevents the valve leaflets from sealingproperly. This heart condition is commonly treated by sewing a ridgedring around the valve. Cinching the tissue around the ring restores thevalve opening to its approximate original size and operating efficiency.

The proper degree of cinching, however, is difficult to determine duringopen heart surgery. This is because the patient is under generalanesthesia, in a prone position, with the chest wide open, and a largeincision in the heart. These factors and others affect the ability totest the modified annulus for its therapeutic affect upon mitral valveleaflet coaptation. Even if the cinching is done well, the tissue maycontinue to change over the patient's lifetime such that the heartcondition returns.

SUMMARY

In one embodiment, a system for treating a heart valve includes anadjustable annuloplasty ring configured to be attached to or near acardiac valve annulus. The adjustable annuloplasty ring includes atubular body member and one or more adjustable members. The tubular bodymember and the one or more adjustable members form a ring shape. Theadjustable annuloplasty ring also includes an internal magnet within thetubular body member. The internal magnet is configured to rotate inresponse to a rotating external magnetic field. The internal magnet iscoupled to the one or more adjustable members to change a dimension ofthe ring shape as the internal magnet rotates.

In certain embodiments, the internal magnet includes a cylindricalmagnet having magnetic poles divided along a plane running the length ofthe cylinder. Similar external magnets may be used in an externaladjustment device that generates the external magnetic field. Theinternal and external magnets may be permanent magnets. In addition, orin other embodiments, one or more electromagnets may be used. Numerousexample embodiments are provided for the adjustable annuloplasty ringand the external adjustment device.

In certain embodiments, a magnetic brake is implanted near a patient'sheart. In the absence of the external magnetic field, the magnetic brakeprevents the internal magnet from rotating. In the presence the externalmagnetic field, the magnetic brake allows the internal magnet to rotate.

Additional aspects and advantages will be apparent from the followingdetailed description of preferred embodiments, which proceeds withreference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a block diagram of a system for adjusting the size of a heartvalve according to one embodiment that includes an annuloplasty ring andan external magnetic driver or adjustment device.

FIG. 1B is an enlarged, cross-sectional view of the annuloplasty ringand the external magnetic adjustment device shown in FIG. 1A accordingto one embodiment.

FIGS. 2A and 2B schematically illustrate a magnet that is usable in theannuloplasty ring shown in FIG. 1A according to one embodiment.

FIGS. 3A and 3B schematically illustrate an end view of the magnet ofthe external magnetic adjustment device placed in parallel with themagnet of the annuloplasty ring according to certain embodiments.

FIG. 4 is a schematic diagram of an external magnetic adjustment deviceincluding two magnets arranged outside of a patient's body according toone embodiment.

FIGS. 5A and 5B schematically illustrate a catheter system used toinsert an adjustment device into a patient's heart according to certainembodiments.

FIG. 6 is a simplified block diagram of a system for adjusting the sizeof a heart valve according to one embodiment.

FIG. 7 is a schematic diagram of an adjustable annuloplasty ringaccording to one embodiment.

FIGS. 8A, 8B, 8C, 8D, and 8E schematically illustrate an annuloplastyring according to one embodiment.

FIG. 9 is a schematic diagram illustrating a partially transparent topview of an annuloplasty ring according to another embodiment.

FIG. 10 is a schematic diagram illustrating a cross-sectional top viewillustrating an annuloplasty ring according to another embodiment.

FIGS. 11A, 11B, and 11C are schematic diagrams of an adjustableannuloplasty ring according to another embodiment.

FIGS. 12A and 12B partially illustrate the annuloplasty ring shown inFIG. 11A in a retracted position (FIG. 12A) and in an expanded position(FIG. 12B) according to certain embodiments.

FIGS. 13A, 13B, and 13C are schematic diagrams of an adjustableannuloplasty ring according to another embodiment.

FIGS. 14A and 14B schematically illustrate one embodiment in which thesuperelasticity of a wire may be compressed so as to allow anannuloplasty ring to be inserted through a trocar.

FIGS. 15A and 15B schematically illustrate an annuloplasty ring having ahinged arm according to one embodiment.

FIGS. 16A, 16B, 16C, 16D, and 16E schematically illustrate alternativelatch embodiments that may be used with the annuloplasty ring shown inFIGS. 15A and 15B according to certain embodiments.

FIGS. 17A, 17B, 17C, 17D, 17E, and 17F are schematic diagrams of anadjustable annuloplasty ring according to another embodiment.

FIG. 18 is a schematic diagram of an adjustable annuloplasty ringaccording to another embodiment.

FIG. 19 is a simplified schematic illustrating an end view of a gearattached to a magnetic motor shown in FIG. 18 according to oneembodiment.

FIGS. 20A and 20B schematically illustrate an annuloplasty ringaccording to another embodiment.

FIG. 21 schematically illustrates an annuloplasty ring according toanother embodiment.

FIG. 22 schematically illustrates an annuloplasty ring according toanother embodiment.

FIGS. 23A, 23B, and 23C schematically illustrate a multi-segmentannuloplasty ring according to one embodiment.

FIG. 24 is a schematic diagram of an annuloplasty ring that includes abidirectional torsion drive cable according to one embodiment.

FIG. 25 is a schematic diagram of an annuloplasty ring that includes anelastic tube according to one embodiment.

FIG. 26 is a schematic diagram of an annuloplasty ring that includes arotatable magnet within a pivot arm according to one embodiment.

FIG. 27 is a schematic diagram of an annuloplasty ring according toanother embodiment.

FIG. 28 is a perspective view of an external magnetic adjustment deviceaccording to one embodiment.

FIGS. 29A, 29B, 29C, and 29D schematically illustrate end views of themagnets of the external magnetic adjustment device shown in FIG. 28according to certain embodiments.

FIGS. 30A and 30B graphically represent example magnetic fieldmeasurements as the magnets of the external magnetic adjustment deviceare rotated according to certain embodiments.

FIG. 31 is a schematic diagram of an external magnetic adjustment devicethat includes two electromagnets according to one embodiment.

FIG. 32 graphically illustrates various parameters of the magneticfields generated by the external magnetic adjustment device shown inFIG. 31 according to one embodiment.

FIG. 33A is a schematic diagram of a superior section view of a heartillustrating an annuloplasty ring implanted in the heart and a magneticbrake assembly implanted outside of the heart according to oneembodiment.

FIG. 33B is a schematic diagram illustrating an end view of a brakemagnet and an internal magnet in the annuloplasty ring shown in FIG. 33Aaccording to one embodiment.

FIGS. 34A and 34B schematically illustrate end views of the brake magnetand the internal magnet of the annuloplasty device according to oneembodiment.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

An adjustable annuloplasty ring allows for the proper degree of cinchingboth during open heart surgery and over the patient's lifetime. In oneembodiment, an annuloplasty ring may be adjusted less-invasively ornon-invasively with the patient alert and postoperatively healed. Inaddition, the annuloplasty ring incorporates the ability to both openand close with fine position control.

The embodiments disclosed herein are generally directed to adjustableannuloplasty rings for mitral valve repair. However, this disclosure isnot limited to the mitral valve and an artisan will recognize from thedisclosure herein that the adjustable rings may be adapted for otherheart valves (e.g., tricuspid valve, aortic valve, and/or pulmonaryvalve) and other vascular structures.

Overview

FIG. 1A is a block diagram of a system for adjusting the size of a heartvalve according to one embodiment that includes an annuloplasty ring 100and an external magnetic driver or adjustment device 102. Forillustrative purposes, FIG. 1B is an enlarged, cross-sectional view ofthe annuloplasty ring 100 and the external magnetic adjustment device102 shown in FIG. 1A. The adjustable annuloplasty ring 100 may beimplanted in a heart 104 of a patient 106 in the same manner as currentrigid annuloplasty rings. Although the heart 104 discussed herein isdescribed in terms of a human heart, an artisan will understand from thedisclosure herein that the patient 106 may include any type of mammal orother animal. The annuloplasty ring 100 in this example is “D” shapedand may be attached, for example, to the mitral valve 107. However, anartisan will recognize from the disclosure herein that other shapes(e.g., circular or “C” shaped rings) may also be used for other openings(e.g., for the tricuspid valve).

The annuloplasty ring 100 includes a permanent magnet 108 that may berotated remotely by one or more magnets 110 in the external magneticadjustment device 102. Rotating the one or more magnets 110 in theexternal magnetic adjustment device 102 in one direction causes theannuloplasty ring 100 to close while turning the one or more magnets 110in the opposite direction causes the annuloplasty ring 100 to open. Theexternal magnetic adjustment device 102 shown in FIGS. 1A and 1B mayinclude an external handpiece that controls the annuloplasty ring 100from outside of the patient's body at a distance d from the annuloplastyring 100. However, other adjustment devices (including percutaneousadjustment devices) will also be described in detail below.

In one embodiment, the annuloplasty ring 100 and adjustment deviceincludes one or more of the magnetic adjustment elements disclosed inU.S. Patent Application Publication No. 2008/0097487, titled “Method andApparatus for Adjusting a Gastrointestinal Restriction Device,” filedJun. 8, 2007, which is assigned to the Assignee of the presentapplication, and which is hereby incorporated by reference herein forall purposes. U.S. Patent Application Publication No. 2008/0097487discloses a gastrointestinal implant system that includes a magneticallyadjustable restriction device having a contact surface configured for atleast partially engaging a surface of a gastrointestinal tract of amammal. The gastrointestinal implant system includes an implantableinterface including a driving element, the driving element beingmoveable and operatively coupled to the adjustable restriction device byan actuator configured to change the dimension or configuration of thecontact surface in response to movement of the driving element. Movementof the driving element is effected by application of a moving magneticfield originating external to the patient.

FIGS. 2A and 2B schematically illustrate a magnet 108 that is usable inthe annuloplasty ring 100 shown in FIG. 1A according to one embodiment.A similarly configured magnet may also be used for the magnet 110 in theexternal magnetic adjustment device 102. The magnet 108 in this exampleembodiment is cylindrical and has magnetic poles (e.g., north “N” andsouth “S”) divided along a plane 200 that runs the length of thecylinder. A rotating magnetic field causes the magnet 108 to rotatearound an axis 202 of the cylinder that passes through the respectivecenters of the cylinder's bases (the “cylindrical axis”).

For example, FIGS. 3A and 3B schematically illustrate an end view of themagnet 110 of the external magnetic adjustment device 102 placed inparallel with the magnet 108 of the annuloplasty ring 100 according tocertain embodiments. For illustrative purposes, FIG. 3A illustrates themagnets 108, 110 aligned for maximum (peak) torque transmission and FIG.3B illustrates the south pole of the magnet 110 of the external magneticadjustment device 102 aligned with the north pole of the magnet 108 ofthe annuloplasty ring 100. Regardless of a current or initial alignmentof the magnets 108, 110, the magnetic fields of the respective magnets108, 110 interact with each other such that mechanically rotating themagnet 110 (e.g., using a stepper motor) in the external magneticadjustment device 102 causes the magnet 108 in the annuloplasty ring 100to rotate. For example, rotating the magnet 110 in a clockwise directionaround its cylindrical axis causes the magnet 108 to rotate in acounterclockwise direction around its cylindrical axis. Similarly,rotating the magnet 110 in a counterclockwise direction around itscylindrical axis causes the magnet 108 to rotate in a clockwisedirection around its cylindrical axis.

The magnet 110 in the external magnetic adjustment device 102 providesaccurate one-to-one control of the magnet 108 in the annuloplasty ring100, assuming sufficient magnetic interaction between the magnets 108,110. In other words, one complete rotation of the magnet 110 in theexternal magnetic adjustment device 102 will cause one complete rotationof the magnet 108 in the annuloplasty ring 100. If the relationshipbetween the number of rotations of the magnet 108 and the size of thering is linear, the size of the annuloplasty ring 108 may be determineddirectly from the number of revolutions since the ring was at its lastknown size. If, however, the relationship between the number ofrevolutions and ring size is not linear, a look-up table based on testedvalues for a particular ring or type of ring may be used to relate thenumber of revolutions to the size of the annuloplasty ring 100. Imagingtechniques may also be used to determine the ring size after it isimplanted in the patient. In addition, or in other embodiments, theannuloplasty ring 100 may include circuitry for counting the number ofrevolutions or determining its own size, and for communicating this datato a user. For example, the annuloplasty ring 100 may include a radiofrequency identification (RF ID) tag technology to power and receivedata from the annuloplasty ring 100.

While placing the magnets 108, 110 in parallel increases rotationaltorque on the magnet 108 in the annuloplasty ring 100, the disclosureherein is not so limited. For example, FIG. 1B illustrates that thecylindrical axis of the magnet 110 in the external magnetic adjustmentdevice 102 may be located at an angle θ with respect to the cylindricalaxis of the magnet 108 in the annuloplasty ring 100. The rotationaltorque on the magnet 108 provided by rotating the magnet 110 increasesas the angle θ approaches zero degrees, and decreases as the angle θapproaches 90 degrees (assuming both magnets 108, 110 are in the samegeometric plane or in parallel planes).

The rotational torque on the magnet 108 in the annuloplasty ring 100also increases by using magnets 108, 110 with stronger magnetic fieldsand/or by increasing the number of magnets used in the external magneticadjustment device 102. For example, FIG. 4 is a schematic diagram of anexternal magnetic adjustment device 102 including two magnets 110(a),110(b) arranged outside of a patient's body 106 according to oneembodiment. An artisan will recognize from the disclosure herein thatthe external magnetic adjustment device 102 is not limited to one or twomagnets, but may include any number of magnets. For example, an exampleembodiment that includes four magnets is described below with respect toFIG. 28. The magnets 110(a), 110(b) are oriented and rotated relative toeach other such that their magnetic fields add together at the ringmagnet 108 to increase rotational torque. A computer controlled motor402 synchronously rotates the external magnets 110(a), 110(b) through amechanical linkage 404 to magnetically rotate the internal magnet 108and adjust the size of the annuloplasty ring 100. One revolution of themotor 402 causes one revolution of the external magnets 110(a), 110(b),which in turn causes one revolution of the ring magnet 108. As discussedabove, by counting motor revolutions, the size of the annuloplasty ring100 may be calculated. In one embodiment, the motor 402 includes agearbox with a known gear ratio such that multiple motor revolutions maybe counted for one magnet revolution.

In another embodiment, a strong electro-magnetic field like that used inMagnetic Resonance Imaging (MRI) is used to adjust the annuloplasty ring100. The magnetic field may be rotated either mechanically orelectronically to cause the magnet 108 in the annuloplasty ring 100 torotate. The patient's body may also be rotated about the axis 202 of themagnet 108 in the presence of a strong magnetic field, like that of anMRI. In such an embodiment, the strong magnetic field will hold themagnet 108 stationary while the ring 100 and patient 106 are rotatedaround the fixed magnet 108 to cause adjustment. The ring size may bedetermined by counting the number of revolutions of the magnetic field,or the patient's body, similar to counting revolutions of the permanentmagnets 110 discussed above.

In another embodiment, the annuloplasty ring 100 may be adjusted duringopen heart surgery. For example, after implanting the annuloplasty ring100 in the heart 104, the heart 104 and pericardium may be closed, andthe regurgitation monitored (e.g., using ultrasound color Doppler).Then, a user (e.g., surgeon) may use a handheld adjustment device 102 toresize the annuloplasty ring based on the detected regurgitation.Additional regurgitation monitoring and ring adjustment may be performedbefore completing the surgery.

In another embodiment, a percutaneously delivered adjustment device isused to resize the annuloplasty ring 100. For example, FIGS. 5A and 5Bschematically illustrate a catheter system 502 used to insert anadjustment device 501 into a patient's heart 104 according to certainembodiments. As shown, the annuloplasty ring 100 may be implanted in theleft atrium 504 of the heart 104 on the upper side 506 of the leaflets508 of the mitral valve 510. However, it is contemplated that theannuloplasty ring 100 may be positioned on the lower side of theleaflets 508. For example, the annuloplasty ring 100 may be positionedin the left ventricle 512. In some non-limiting embodiments, theannuloplasty ring 100 is snaked through the chordae tendineae and thenplaced against the lower surfaces of the leaflets 508. Alternatively,the chordae tendineae may be cut to provide a delivery path forimplantation of the annuloplasty ring 100. In certain embodiments, theannuloplasty ring 100 may be implanted at other locations in thevasculature system, or at any other position within a patient's body106. For example, the annuloplasty ring 100 may be implanted at alocation proximate to the tricuspid valve 514. The annuloplasty ring 100may be positioned on the upper side (e.g., in the right atrium 516) orlower side (e.g., in the right ventricle 518) of the tricuspid valve 514to improve the efficacy of the tricuspid valve 514.

As shown in FIG. 5A, the catheter system 502 enters the heart 104through the inferior vena cava 520 into the right atrium 516 so as toposition the adjustment device 501 proximate the interatrial septum 522.The catheter system 502 may alternatively enter from the superior venacava. As discussed above, the adjustment device 501 includes one or moremagnets configured to interact with a magnetic field of a magnet in theannuloplasty ring 100. The catheter system 502 is configured to adjustthe size of the annuloplasty ring 100 through the interatrial septum 522by rotating the one or more magnets in the adjustment device 501 using aflexible drive shaft connected to an external hand crank operated by auser (e.g., physician) or a processor-controlled motor.

As shown in FIG. 5B, the catheter system 502 in another embodiment mayenter the heart 104 through the inferior vena cava 520 into the rightatrium 516, and through a hole (e.g., through the fossa ovalis) in theinteratrial septum 522 into the left atrium 504. The catheter system 502may alternatively enter from the superior vena cava. Although not shownin FIG. 5B, the catheter system 502 may locate the adjustment device 501proximate the magnet in the annuloplasty ring 100. As discussed above,the adjustment device 501 includes one or more magnets configured tointeract with a magnetic field of the magnet in the annuloplasty ring100. The catheter system 502 is configured to adjust the size of theannuloplasty ring 100 by rotating the one or more magnets in theadjustment device 501 using a flexible drive shaft connected to anexternal hand crank operated by a user (e.g., physician) or a processorcontrolled motor.

FIG. 6 is a simplified block diagram of a system 600 for adjusting thesize of a heart valve according to one embodiment. The simplifiedembodiment shown in FIG. 6 is provided to illustrate the basic operationof the annuloplasty ring 100. However, more detailed embodiments areprovided below.

The system 600 includes an adjustable annuloplasty ring 100 and anexternal magnetic adjustment device 102. The annuloplasty ring 100includes a magnet 108 in a magnet housing 610. The magnet 108 iscylindrical and is configured to rotate around its cylindrical axis whenexposed to a rotating magnetic field. The magnet 108 is coupled to aproximal end of a lead screw 612. A spindle nut 614 is threaded onto thelead screw 612. A wire 616 is coupled to the magnet housing 610 and thespindle nut 614 to form a loop. The wire 616 may include, for example,stainless steel or superelastic nitinol.

The external magnetic adjustment device 102 includes a magnet 110 in amagnet housing 618 coupled to a drive shaft 620. The drive shaft 620 maybe connected to a stepper motor 622 coupled to a motor controller/drive624. The controller/drive 624 may include, for example, a microprocessoror personal computer. The controller/drive 624 is configured to controlthe position, rotation direction, rotation speed, speed ramp up/down,and other parameters of the stepper motor 622. The stepper motor 622rotates the shaft 620, which in turn rotates the magnet 110. Asdiscussed above, in certain embodiments the shaft 620 and the magnet 110may be covered with a protective material (e.g., plating) and insertedinto the heart 104 through a catheter.

In operation, the rotating magnet 110 in the external magneticadjustment device 102 causes the magnet 108 in the annuloplasty ring 100to rotate. The rotating magnet 108 causes the lead screw 612 to rotate,which in turn causes the spindle nut 614 to move along the threads ofthe lead screw 612 to either increase or decrease the size of the loopformed by the wire 616.

In certain embodiments, it is desirable to symmetrically adjust the sizeof the annuloplasty ring 100 in an anterior/posterior (AP) direction.For example, FIG. 7 is a schematic diagram of an adjustable annuloplastyring according to one embodiment. The annuloplasty ring 100 is “D”shaped having an AP dimension along the curved portion of the “D” and acommissure to commissure or “CC” dimension along the straight portion ofthe “D.” Adjusting the annuloplasty ring 100 from an open to a closedposition, or vice-versa, changes the AP dimension without substantiallychanging the CC dimension. Further, the AP dimension changessymmetrically in that both the left and right sides of the annuloplastyring 100 change by substantially the same amount. Certain of thefollowing embodiments include these features.

Example Annuloplasty Ring Embodiments

In certain embodiments discussed herein, including those discussed aboveas well as those discussed below, the materials of the annuloplasty ring100 are selected for compatibility with long-term contact with humantissue. For example, these materials may include nitinol, stainlesssteel, titanium alloys, cobalt alloys, bio-compatible plastics, andother bio-compatible materials. In certain embodiments, the annuloplastyring 100 may be covered with a polyester or Dacron® fabric or othersuturable material. In addition or in other embodiments, theannuloplasty ring 100 may also include eyelets used for suturing. Themagnet 108 discussed in certain embodiments herein may include arare-earth magnet and may be plated (e.g., with nickel or gold) orencapsulated in a suitable bio-compatible material, such as thematerials discussed above, to reduce or prevent harm to the patient anddamage to the magnet. Bearings are included in certain embodiments.These bearings may be of any suitable type including, for example, ballbearings or jewel bearings.

FIGS. 8A, 8B, 8C, 8D, and 8E schematically illustrate an annuloplastyring 100 according to one embodiment. FIG. 8A is a partially transparenttop view of the annuloplasty ring 100 in an AP extended or plusposition. FIG. 8B is a partially transparent top view of theannuloplasty ring 100 in an AP retracted or minus position. FIG. 8Cschematically illustrates a side view of the annuloplasty ring 100. FIG.8D is a partially transparent perspective view of the annuloplasty ring100. FIG. 8E is another partially transparent top view of theannuloplasty ring 100.

The annuloplasty ring 100 includes a body tube 810 for enclosing amagnet housing 812 (including a first end 812(a) and a second end812(b)) that encases a magnet 108 (FIG. 8E). A first end of the bodytube 810 is connected to a first fixed arm 816 and a first end of themagnet housing 812(a) crimps to a first end of a drive cable 818. Thefirst fixed arm 816 is connected to a first swivel arm 820 at a firstpin joint 822 (e.g., pivot point). A second end of the body tube 810 isconnected to a second fixed arm 824 that is connected to a second swivelarm 826 at a second pin joint 828. The annuloplasty ring 100 alsoincludes a lead screw 830 having a first end threaded into a drive nut832 that is connected to the second swivel arm 826 at a third pin joint834. A second end of the lead screw is connected to a drive spindle 836that is connected to a second end of the drive cable 818. A spindle nut838 is threaded onto the lead screw 830. The spindle nut 838 retains thedrive spindle 836 into the first swivel arm 820.

The magnet housing 812 is engaged with the first fixed arm 816 and thesecond fixed arm 824 such that rotating the magnet 108 (e.g., using theexternal magnetic adjustment device 102) causes the magnet housing 812to rotate. The rotating magnet housing 812 turns the drive cable 818,which turns the drive spindle 836. The drive spindle 836 rotates thelead screw 830 such that it screws into or out of the drive nut 832. Asthe lead screw 830 screws into or out of the drive nut 832, the swivelarms 820, 826 pivot at their respective pin joints 822, 828, 834 toreduce or enlarge the size of the ring opening in the AP dimension.

FIG. 9 is a schematic diagram illustrating a partially transparent topview of an annuloplasty ring 100 according to another embodiment. Theannuloplasty ring 100 shown in FIG. 9 includes a body tube 910 forenclosing a magnet housing 912 that encases a magnet 108. A first end ofthe body tube 910 is connected to a first fixed arm 914 and a first endof the magnet housing 912 crimps to a first end of a first drive cable(not shown). The first fixed arm 914 is connected to a first swivel arm916 at a first pin joint 918. A second end of the body tube 910 isconnected to a second fixed arm 920 and a second end of the magnethousing 912 crimps to a first end of a second drive cable (not shown).The second fixed arm 920 is connected to a second swivel arm 922 at asecond pin joint 924.

The annuloplasty ring 100 also includes an extension 926 thatsymmetrically moves in and out in the AP dimension as the magnet 108turns. A first end of a first lead screw 928 is connected to the firstswivel arm 916 through a first drive spindle 930 that is connected tothe second end of the first drive cable. A second end of the first leadscrew 928 is threaded into a first end of the extension 926. A first endof a second lead screw 932 is connected to the second swivel arm 922through a second drive spindle 934 that is connected to the second endof the second drive cable. A second end of the second lead screw 932 isthreaded into a second end of the extension 926. The extension 926 actsas a drive nut for a first lead screw 928 and the second lead screw 932.The first lead screw 928 and the second lead screw 932 both screw intoor out of the extension 926 at the same time, causing the swivel arms916, 922 to pivot about their respective pin joints 918, 924. In such anembodiment, one of the lead screws 928, 932 has “right-handed” threadsand the other has “left-handed” threads such that both lead screws 928,932 tighten or loosen together.

FIG. 10 is a schematic diagram illustrating a cross-sectional top viewillustrating an annuloplasty ring 100 according to another embodiment.The annuloplasty ring 100 shown in FIG. 10 includes a magnet 108, aflexible lead screw 1010, an elastic covering 1012, and a wire (notshown) extending from a first end of the flexible lead screw 1010 to afixed point. The elastic covering 1012 may include, for example, abiocompatible polymer such as, for instance, polyurethane silicone or asilicone-urethane copolymer. The magnet 108 includes a hollow passage1014 and a threaded nut section 1015 or bearings through which theflexible lead screw 1010 passes (e.g., either to the right or to theleft) as the magnet 108 turns. Turning the magnet 108 in one directionexerts force on the flexible lead screw 1010, which is transmitted tothe wire, which in turn causes the elastic covering 1012 to contractinwardly at predetermined locations 1016. The contraction symmetricallyreduces the ring opening. Rotating the magnet 108 in the oppositedirection reverses the contraction.

FIG. 11A is a schematic diagram of an adjustable annuloplasty ring 100according to another embodiment. The annuloplasty ring 100 includes apermanent magnet 1102 configured to rotate within a magnet housing 1104.The magnet 1102 is cylindrical and is configured to rotate around itscylindrical axis when exposed to a rotating magnetic field. FIG. 11B isa schematic diagram of a front view of the magnet 1102 shown in FIG. 11Aaccording to one embodiment. FIG. 11C is a schematic diagram of a sideview of the magnet 1102 shown in FIG. 11A according to one embodiment.Like the magnet 108 shown in FIGS. 2A, 2B, 4, and 6, the magnet 1102 hasmagnetic poles (e.g., north “N” and south “S”) divided along the plane200 that runs the length of the cylinder. The magnet 1102 may include arare earth magnet and may be plated (e.g., with nickel or gold) and/orsuitably encapsulated to prevent harm to the patient and damage to themagnet 1102. Unlike the magnet 108 shown in FIGS. 2A, 2B, 4, and 6,however, the magnet 1102 includes a hollow region 1106 running along thelength of the cylinder between the N and S poles. The hollow region 1106may be threaded or may contain a threaded insert 1108 through which alead screw 1110 is pulled into and out of the magnet 1102.

A wire 1112 is coupled between the magnet housing 1104 (e.g., by a weld1114) and an end of the lead screw 1110. In another embodiment, aseparate lead screw 1110 is not used. Rather, threads are formed or cutinto the end of the wire 1112 such that the wire 1112 interfacesdirectly with the threads in the magnet 1102 (e.g., the threaded insert1108). The wire 1112 may include, for example, superelastic nitinol.

In one embodiment, the annuloplasty ring 100 includes bearings 1116 toanchor the spinning magnet 1102. When the magnet 1102 is exposed to arotating magnetic field in one direction, the magnet 1102 pulls the leadscrew 1110 and/or threaded wire 1112 into the magnet 1102, which in turnreduces the size of the loop formed by the wire 1112. When the magnet1102 is exposed to the magnetic field rotating in the oppositedirection, the magnet 1102 pushes the lead screw 1110 and/or thethreaded wire 1112 out of the magnet 1102, which in turn increases thesize of the loop formed by the wire 1112.

FIGS. 12A and 12B partially illustrate the annuloplasty ring 100 shownin FIG. 11A in a retracted position (FIG. 12A) and in an expandedposition (FIG. 12B) according to certain embodiments. In FIG. 12A, therotation of the magnet 1102 (e.g., clockwise) pulls the lead screw 1110and/or threaded wire 1112 further into the magnet 1102 and the magnethousing 1104. In FIG. 12B, the rotation of the magnet 1102 (e.g.,counter-clockwise) pushes the lead screw 1110 and/or threaded wire 1112further out of the magnet 1102 and the magnet housing 1104. In oneembodiment, a portion of the lead screw 1110 and/or the threads in thewire 1112 may extend beyond the magnet housing 1104 when theannuloplasty ring 100 is in the extended position. In anotherembodiment, the lead screw 1110 and/or the threads in the wire 1112remain within the magnet housing 1104 in both the extended and retractedpositions. Moving the lead screw 1110 and or the threaded portion of thethreads in the wire 1112 into and out of the magnet 1110 allows improvedcontrol for symmetrically adjusting the annuloplasty ring 100 in the APdirection, as discussed above in relation to FIG. 7.

FIGS. 13A, 13B, and 13C are schematic diagrams of an adjustableannuloplasty ring 100 according to another embodiment. In thisembodiment, the annuloplasty ring 100 includes arm extensions or “horns”1310, 1312 attached to each end of the magnet housing 1104. The horns1310, 1312 may include a suitable rigid or semi-rigid material such asmetal or plastic. The horns 1310, 1312 redirect or angle a wire 1314forming the loop of the annuloplasty ring 100. For example, the horns1310, 1312 may redirect the wire 1314 approximately 90° from thecylindrical axis of the magnet 1102 within the housing 1104. Thus, thehorns 1310, 1312 further maintain the “D” shape of the annuloplasty ring100 such that it is substantially only adjusted in the AP direction(e.g., expansion/contraction of the loop is perpendicular to therotation of the magnet 1102). In one embodiment, the annuloplasty ring100 includes silicone tubing 1317 sealed to each horn 1310, 1312. Thewire 1314 extends through the silicone tubing 1317. The silicone tubing1317 stretches and contracts to accommodate circumferential changes tothe loop in the annuloplasty ring 100.

FIG. 13B is a cross-sectional view of the housing 1104 shown in FIG. 13Aaccording to one embodiment. In this embodiment, the magnet 1102includes a first threaded insert 1318 and a second threaded insert 1320.The two inserts 1318, 1320 have opposite threaded orientations. Forexample, the first threaded insert 1318 may have a right-hand threadorientation and the second threaded insert 1320 may have a left-handthread orientation. Both ends of the magnet 1102 may be coupled tobearings 1116 to support the spinning magnet 1102. Each end of the wire1314 is threaded to interface with its respective threaded insert 1318,1320 such that rotating the magnet 1102 in one direction pulls the endsof the wire 1314 toward each other and the center of the magnet, androtating the magnet in the opposite direction pushes the ends of thewire 1314 away from each other and the center of the magnet 1102.

As also shown in FIG. 13B, the housing 1104 and horns 1310, 1312 aresealed from the outside environment. The housing 1104 may include twoportions that are welded together along a weld line 1321. Further, thehorns 1310, 1312 are bonded to the housing 1104 to create a hermeticseal 1322. Lubricant 1324 may also be sealed within portions of thehousing 1104 to provide for proper operation of the bearings 1116.

FIG. 13C is a cross-sectional view of the interface between the horn1310 and the silicone tubing 1317 according to one embodiment. As shown,in certain embodiments, the annuloplasty ring 100 may include a Dacron®covering 1326 (or other polyester covering) or a covering of othersuitable material. The inner pathway of the horn 1310 may include alubricant such as polytetrafluoroethylene (as known as PTFE or Teflon®),silicone oil, grease, etc. to reduce friction between the wire 1314 andthe horn 1310 during adjustment of the annuloplasty ring 100. Thesilicone tubing 1317 attaches to the horn 1310 and may provide an areainto which sutures may be placed to secure the annuloplasty ring 100 toheart tissue. As discussed above, the silicone tubing 1317 also provideselasticity to accommodate expansion and contraction of the annuloplastyring 100.

In certain embodiments, the annuloplasty ring 100 is configured forimplantation into a heart through a narrow trocar or similar device. Forexample, FIGS. 14A and 14B schematically illustrate one embodiment inwhich the superelasticity of the wire 1314 (e.g., including a materialsuch as nitinol), may be compressed so as to allow the annuloplasty ring100 to be inserted through a trocar. In FIG. 14A, the size of theannuloplasty ring 100 in the AP dimension is approximately 20 mm or moreaccording to some embodiments. This size may correspond to thedimensions of the annuloplasty ring 100 both before and after beinginserted through the trocar. In FIG. 14B, the annuloplasty ring 100 iscompressed so as to pass through the trocar. In this configuration, thesize of the annuloplasty ring 100 in the AP dimension is approximately10 mm or less according to some embodiments. The superelasticity of thewire 1314 allows for extreme flexibility, yet still provides thenecessary strength after implantation for annuloplasty.

Other embodiments also allow for the annuloplasty ring 100 to beinserted through a trocar. For example, FIGS. 15A and 15B schematicallyillustrate an annuloplasty ring 100 having a hinged arm 1510 accordingto one embodiment. The hinged arm 1510 is connected to the housing 1104through a pin joint 1513. The other end of the hinged arm 1510 includesa latch 1514 for engaging the superelastic wire 1314 after implantationthrough the trocar. For example, the latch 1514 may include a socketconfigured to receive a “snap-in” lock pin 1516 attached to the free endof the wire 1314 during implantation. Thus, the annuloplasty ring 100may be inserted into a very small orifice without worry of damaging thewire 1314.

Alternative latch embodiments that may be used with the annuloplastyring 100 shown in FIGS. 15A and 15B are schematically illustrated inFIGS. 16A, 16B, 16C, 16D, and 16E. FIG. 16A, for example, illustrates anembodiment wherein the socket latch 1514 and the lock pin 1516 arelocated anywhere along the wire 1314. In other words, the socket latch1514 is not directly connected to the hinged arm 1510, as shown in FIGS.15A and 15B. In FIG. 16B, the latching mechanism includes a “ramp andpawl” device in which a pin 1610 having a ramped surface 1612 and avertical surface 1614 is inserted into a receptacle 1616 having aslanting protrusion 1618. The slanting protrusion 1618 is angled andsufficiently flexible so as to allow the slanted surface 1612 to proceedinto the receptacle 1616. However, once inserted, the slantingprotrusion 1618 interfaces with the vertical surface 1614 of the pin1610 so as to prevent the pin 1610 from exiting the receptacle 1616, atleast under normal operating conditions. In FIG. 16C, a “knuckle” stylelatch 1621 provides coupling similar to that used in trains. In FIG.16D, the latch includes a threaded end 1620 configured to be screwedinto a threaded nut 1622. In FIG. 16E, the latch includes a “T-bar” 1624configured to be received by an appropriately shaped receptacle 1626. Anartisan will recognize, of course, that the embodiments shown in FIGS.16A, 16B, 16C, 16D, and 16E are provided by way of example only, andthat many other different types of latches may also be used.

FIGS. 17A, 17B, 17C, 17D, 17E, and 17F are schematic diagrams of anadjustable annuloplasty ring 100 according to another embodiment. Inthis embodiment, the annuloplasty ring 100 includes a first arm 1710attached to the housing 1104, a second arm 1712 attached to the housing1104, and a third arm 1714 extending between the first arm 1710 and thesecond arm 1712. As shown by the curved arrows in FIG. 17A, at least oneof the first arm 1710 and the second arm 1712 may be pushed into or outof the housing 1104 in response to the rotation of the internal magnet108 discussed above. The third arm 1714 is connected to at least one ofthe first arm 1710 and the second arm 1712 with a folding hinge 1716that allows the loop portion of the annuloplasty ring 100 to be foldedfor insertion through a trocar. FIG. 17A illustrates a front view of the“open” or unfolded annuloplasty ring 100. FIG. 17B illustrates a frontview of the “folded” annuloplasty ring 100 for insertion through thetrocar. FIGS. 17C and 17D provide respective close-up views of the hinge1716. After inserting the annuloplasty ring 100 through the trocar, thehinges are opened and may be locked in the open position forimplantation around a heart valve (e.g., the mitral valve). For example,FIGS. 17E and 17F illustrate a locking mechanism that includes a lockingsleeve 1720, a bias element 1722 (e.g., spring), and a mechanical stop1724. In FIG. 17E, the locking sleeve 1720 is located above the hinge1716. As the hinge 1716 is opened, the bias element 1722 pushes thelocking sleeve 1720 over the hinge 1716 until it makes contact with thestop 1724, as shown in FIG. 17F. Thus, once the hinge 1716 is open, thebias element 1722 and the stop 1724 hold the locking sleeve 1720 inplace such that the hinge 1716 cannot be opened, at least not withoutuser intervention.

FIG. 18 is a schematic diagram of an adjustable annuloplasty ring 100according to another embodiment. In this embodiment, the annuloplastyring 100 includes a housing 1810, a magnetic motor 108, and a wire 616,such as the magnetic motor 108 and wire 616 discussed above in relationto FIGS. 1B, 2A, 2B, 3, 4, and 6. The wire 616 includes a fixed end 1812attached to the housing 1810 and a moving end 1814 attached to a rack1816 located within the housing 1810. In one embodiment, the rack 1816is cut or formed within the wire 616 itself. The magnetic motor 108rotates in the presence of a rotating magnetic field so as to turn agear 1818. The gear 1818 is in mechanical communication with the rack1816 such that turning the gear 1818 slides the rack 1816 back and forthto change the size of the loop of the annuloplasty ring 100. Forillustrative purposes, FIG. 19 is a simplified schematic illustrating anend view of the gear 1818 attached to the magnetic motor 108 accordingto one embodiment.

FIGS. 20A and 20B schematically illustrate an annuloplasty ring 100according to another embodiment. FIG. 20A is a perspective view of theannuloplasty ring 100. FIG. 20B is a partially transparent top view ofthe annuloplasty ring 100. The annuloplasty ring 100 includes a bodytube 2010 for enclosing a magnet 108. The magnet 108 is cylindrical andboth ends thereof are coupled to bearings 2014 to allow the magnet 108to rotate when exposed to a rotating magnetic field. The magnet 108 hasmagnetic poles divided along a plane that runs along the length of thecylinder. The magnet 108 includes a hollow region 2015 running along thelength of the cylinder between the magnetic poles. The hollow region2015 may be threaded or may include a threaded insert through which alead screw 2030 is pulled (e.g., right and left as shown in FIG. 20B)through the magnet 108.

A first end of the body tube 2010 is connected to a first fixed arm 2016and a first end of the lead screw 2030 crimps or otherwise attaches to afirst end of a drive cable 2018. The first fixed arm 2016 is connectedto a first swivel arm 2020 at a first pin joint 2022. A second end ofthe body tube 2010 is connected to a second fixed arm 2024 that isconnected to a second swivel arm 2026 at a second pin joint 2028. Asecond end of the drive cable 2018 crimps or otherwise attaches to apush rod 2032. A second end of the push rod 2032 is connected to thesecond swivel arm 2026 at a third pin joint 2034.

When the magnet 108 is exposed to a rotating magnetic field (e.g., usingthe external magnetic adjustment device 102), the magnet 108 rotates.The connection of the drive cable 2018 between the lead screw 2030 andthe push rod 2032 prevents the lead screw 2030 from rotating along withthe magnet 108. Rather, the rotating magnet 108 causes the lead screw2030 to push and pull the drive cable 2018 into and out of the magnet108, which causes the swivel arms 2020, 2026 to pivot at theirrespective pin joints 2022, 2028, 2034 to reduce or enlarge the size ofthe ring opening in the AP dimension. For example, the first pin joint2022 may rotate around a first axis 2036 and the second pin joint 2028may rotate around a second axis 2038 (which is parallel to the firstaxis 2036) such that the swivel arms 2020, 2026 move in a first plane.

In addition, or in other embodiments, the annuloplasty ring 100 isconfigured to change shape in a second plane. For example, one or moreof the pin joints 2022, 2028, 2034 shown in FIG. 20B may be replaced byball joints (or pin joints that rotate in a different direction). Insuch an embodiment, the ball joints may be configured to rotate out ofthe first plane when the rotating magnet 108 pushes or pulls the drivecable 2018. For example, first joint 2022 and/or the second joint 2028may rotate at an angle α with respect to the second axis 2038. In onesuch embodiment, the annuloplasty ring 100 is configured to form asaddle shape when the rotating magnet 108 pushes or pulls the drivecable 2018.

FIG. 21 schematically illustrates an annuloplasty ring 100 according toanother embodiment. The embodiment illustrated in FIG. 21 is similar tothe embodiment shown in FIGS. 20A and 20B, except that the push rod 2032is hollow to allow the drive cable 2018 to be inserted and securedtherein. The annuloplasty ring 100 in FIG. 21 also includes a coupler2110 to attach the push rod 2032 and/or the drive cable 2018 to thesecond swivel arm 2026 at the third pin joint 2034. As the rotatingmagnet 108 pushes and pulls the drive cable 2018, the drive cable 2018pushes and pulls the push rod 2032 through the first swivel arm 2020,which causes the swivel arms 2020, 2026 to pivot at their respective pinjoints 2022, 2028, 2034 to reduce or enlarge the size of the ringopening in the AP dimension. As a safety feature, the first swivel arm2020 includes one or more divots or crimps 2112 configured to engage thesliding end of the push rod 2032 to prevent it from exiting the secondswivel arm 2020.

FIG. 22 schematically illustrates an annuloplasty ring 100 according toanother embodiment. The annuloplasty ring 100 includes the body tube2010, magnet 108, bearings 2014, first fixed arm 2016, second fixed arm2024, drive cable 2018, first pin joint 2022, and second pin joint 2028discussed above in relation to FIGS. 20A and 20B. In this embodiment,however, the magnet 108 need not be threaded, though it may or may notbe hollow to facilitate attachment of the drive cable 2018. A first endof the drive cable 2018 is attached to either the magnet 108 such thatrotating the magnet 108 causes the drive cable 2018 to rotate.

The annuloplasty ring 100 shown in FIG. 22 includes a first swivel arm2210 attached to the first fixed arm 2016 at the first pin joint 2022.The first swivel arm 2210 is coupled to a lead screw 2212 using abearing 2213. A second end of the drive cable 2018 is attached to afirst end of the lead screw 2213 such that rotating the drive cable 2018causes the lead screw 2212 to rotate about the bearing 2213. The bearing2213 allows the lead screw to rotate freely without detaching from thefirst swivel arm 2210. A second swivel arm 2214 is attached to thesecond fixed arm 2024 at the second pin joint 2028. The second swivelarm 2214 includes a threaded drive nut 2216 that engages the threads ofthe threads of the lead screw 2212. As the lead screw 2212 screws intoor out of the drive nut 2216, the swivel arms 2210, 2214 pivot at theirrespective pin joints 2022, 2028 to reduce or enlarge the size of thering opening in the AP dimension. The lead screw 2212 may include an endstop 2218 to prevent the lead screw 2212 from being removed (e.g.,unscrewed) from the drive nut 2216.

An artisan will recognize that many changes may be made to theannuloplasty ring embodiments disclosed herein. For example, FIGS. 23A,23B, and 23C illustrate a multi-segment annuloplasty ring 100 accordingto one embodiment. The annuloplasty ring 100 includes a body tube 2310attached to a first magnetic drive segment 2312 at a first pin joint2314 and a second magnetic drive segment 2316 at a second pin joint2318. The annuloplasty ring 100 may include one or more additionalmagnetic drive segments 2320 (four shown in the example of FIG. 23A)coupled between the first magnetic drive segment 2312 and the secondmagnetic drive segment 2316. The magnetic drive segments 2312, 2316,2320 are coupled to one another with respective lead screws 2322 (fiveshown in the example of FIG. 23A). Safety wires 2324 (five shown in theexample of FIG. 23A) are attached between each lead screw 2322 and arespective magnetic drive segment 2318, 2320. Each magnetic drivesegment 2312, 2316, 2320 includes a magnet 108 (FIGS. 23B and 23C) thatmay be rotated using a changing magnetic field to drive the respectivelead screws 2322. Thus, the distance between adjacent magnetic drivesegments 2312, 2316, 2320 may be selectively adjusted. In oneembodiment, the position of each magnetic drive segment 2312, 2316, 2320may be individually adjusted.

FIG. 23B schematically illustrates an example magnetic drive segment2320 according to one embodiment. The magnetic drive segment 2320includes a link housing 2326 having a first end with a threaded drivenut 2328 for receiving a first lead screw 2322 (not shown in FIG. 23B).A second end of the link housing 2326 includes a hollow magnet 108within a magnet housing 2330. The magnet 108 and magnet housing 2332 areattached to bearings 2332 that allow them to rotate in the presence of arotating magnetic field. A second lead screw 2322 is connected to androtates with the magnet 108, and is attached to a first end of a safetywire 2324. A second end of the safety wire 2324 is attached to a safetystop 2336 configured to attach to one of the other magnetic drivesegments 2312, 2316, 2320 shown in FIG. 23A.

FIG. 23C schematically illustrates an example magnetic drive segment2320 according to another embodiment. The magnetic drive segment 2320shown in FIG. 23C includes a link housing 2338 having a first end fixedto a threaded stud 2340. The threaded stud 2340 is configured to bereceived by one of the other magnetic drive segments 2312, 2316, 2320shown in FIG. 23A. Thus, in this embodiment, some or all of the separatedrive screws 2322 are not used. A second end of the link housing 2338includes a hollow magnet 108 within a magnet housing 2342. The magnet108 and magnet housing 2342 are attached to bearings 2344 that allowthem to rotate in the presence of a rotating magnetic field. An innermagnet housing 2346 is threaded to receive a lead screw 2322 or athreaded stud fixed to one of the other magnetic drive segments 2312,2316, 2320 shown in FIG. 23A.

FIG. 24 is a schematic diagram of an annuloplasty ring 100 that includesa bidirectional torsion drive cable 2410 according to one embodiment.The annuloplasty ring 100 includes a C-shaped base 2412 that passesthrough a hollow magnet 108. In the presence of a rotating magneticfield, the hollow magnet 108 rotates on bearings 2414 attached to thebase 2412. A first end of the base 2412 is attached to a first swivelarm 2416 at a first pin joint 2418. The first swivel arm 2416 includes athreaded section 2420. A first end of the bidirectional torsion drivecable 2410 is attached to a first end of the magnet 108. A second end ofthe bidirectional torsion cable 2410 includes a drive nut 2422 thatengages the threaded section 2420 of the first swivel arm 2416. In oneembodiment, the first swivel arm 2416 includes a curved lead-in section2426 to assist in controlling the shape of the bidirectional torsiondrive cable 2410. In addition, or in other embodiments, the annuloplastyring 100 may also include a second swivel arm 2428 connected to a secondend of the base 2412 at a second pin joint 2430. The second swivel arm2428 also assists in controlling the shape of the bidirectional torsiondrive cable 2410. As the magnet 108 rotates, the drive nut 2422 drawsthe threaded section 2420 of the first swivel arm 2416 into and out ofthe bidirectional torsion drive cable 2410 to adjust the size of theannuloplasty ring 100. The bidirectional torsion drive cable 2410 mayinclude, for example, a flexible shaft available from S.S. WhiteTechnologies, Inc., of Piscataway, N.J.

FIG. 25 is a schematic diagram of an annuloplasty ring 100 that includesan elastic tube 2510 according to one embodiment. The elastic tube 2510extends between the ends of a rigid base 2512 to form a D-shaped ring. Amagnet 108 with internal threads (as discussed above) is configured torotate within the base 2512 in the presence of a rotating magneticfield. A first end of a drive cable 2514 may be threaded so as to engagethe internal threads of the magnet 108. In another embodiment, as shownin FIG. 25, the first end of the drive cable 2514 is attached to athreaded drive screw 2513 configured to engage the internal threads ofthe magnet 108. A second end of the drive cable 2514 is attached to ananchor point 2516 within the elastic tube 2510. As the magnet 108rotates, the drive cable 2514 is drawn into and out of the magnet 108.The elastic tube 2510 includes bending regions 2518 and an expandableregion 2520. The drive cable 2514 acts as a draw string to control thecircumference of the expandable section 2520 of the elastic tube 2510.In one embodiment, the elastic tube 2510 comprises superelastic nitinol.

FIG. 26 is a schematic diagram of an annuloplasty ring 100 that includesa rotatable magnet 108 within a pivot arm 2610 according to oneembodiment. The annuloplasty ring 100 includes a C-shaped base 2612attached to a first end to the pivot arm 2610 at a first pin joint 2614.A second end of the base 2612 is attached to a first end of a secondpivot arm 2616 at a second pin joint 2618. A second end of the secondpivot arm 2616 is attached to a drive nut 2620 at a third pin joint2622. As discussed above, the magnet 108 (or an attached magnet housing)may be coupled to bearings 2624 that allow the magnet 108 to rotatewithin the pivot arm 2610. The magnet 108 (or a magnet housing) isattached to a first end of a lead screw 2626. A second end of the leadscrew 2626 interfaces with the drive nut 2620. Thus, as the magnet 108rotates in the presence of a rotating magnetic field, the lead screw2626 is drawn into and out of the drive nut 2620 in the direction of theillustrated arrow 2628 to adjust the size of the annuloplasty ring 100.

FIG. 27 is a schematic diagram of an annuloplasty ring 100 according toanother embodiment. The annuloplasty ring 100 includes a C-shaped base2712 having a first end attached to a first end of a first pivot arm2714 at a first pin joint 2716. A second end of the base 2712 isattached to a first end of a second pivot arm 2718 at a second pin joint2720. A second end of the first pivot arm 2714 is attached to a firstcoupler 2721 at a third pin joint 2724. A second end of the second pivotarm 2718 is attached to a second coupler 2723 at a fourth pin joint2726. A magnet 108 is configured to rotate on bearings 2728 within adrive housing 2722. The first coupler 2721 is attached to a first leadscrew 2730 and the second coupler 2723 is attached to a second leadscrew 2732. Each lead screw 2730, 2732 is configured to interface withrespective internal threads of the magnet 108. The first lead screw 2730and the second lead screw 2732 are threaded in opposite directions. Forexample, the first lead screw 2730 may have left-hand threads and thesecond lead screw 2732 may have right-hand threads. Thus, as the magnet108 rotates in the presence of a rotating magnetic field, both leadscrews 2730, 2732 are either drawn into the magnet 108, or both leadscrews 2730, 2732 are drawn out of the magnet 108 in the direction ofthe illustrated arrows 2734 to adjust the size of the annuloplasty ring100.

Example External Magnetic Adjustment Device

FIG. 28 is a perspective view of an external magnetic adjustment device102 according to one embodiment. The external magnetic adjustment device102 includes a first cylindrical magnet 110(a), a second cylindricalmagnet 110(b), a third cylindrical magnet 110(c), and a fourthcylindrical magnet 110(d) (referred to collectively as magnets 110). Inone embodiment, the magnets 110 are permanent magnets. In anotherembodiment, the magnets 110 are electromagnets configured to beselectively activated. The first magnet 110(a) and the second magnet110(b) are attached to a first arm 2810. The third magnet 110(c) and thefourth magnet 110(d) are attached to a second arm. The first arm 2810and the second arm 2812 are configured to slide relative to each otherin opposite directions along a first rail 2814 and a second rail 2816.Thus, a patient's chest may be placed between the magnets 110 of thefirst arm 2810 and the second arm 2812 during adjustment of a magneticannuloplasty ring (such as the annuloplasty rings 100 discussed above)implanted within the patient's heart.

As shown in FIG. 28, the first arm 2810 may be connected to a firstscrew 2818 threaded in a first direction (e.g., right-hand threads) andthe second arm 2812 may be connected to a second screw 2820 threaded ina second direction (e.g., left-hand threads). The first screw 2818 isconnected to the second screw 2820 by a coupler 2830 such that bothscrews 2818, 2820 turn at the same time. A user may turn the screws2818, 2820 using, for example, a hand crank 2832 to adjust the relativepositions of the arms 2810, 2812. In another embodiment, a motor (notshown) under the control of a controller (such as the controller 624shown in FIG. 6) may be used to turn the screws 2818, 2820.

The first arm 2810 includes a first stepper motor 2834 configured torotate the first magnet 110(a) and the second magnet 110(b). Forexample, an axle (not shown) may be connected to the first magnet 110(a)and a coupling such as a drive chain (not shown) may couple the firstmagnet 110(a) to the second magnet 110(b) such that the magnets 110(a),110(b) rotate together in the same direction. Similarly, the second arm2812 includes a second stepper motor 2834 configured to rotate the thirdmagnet 110(c) and the fourth magnet 110(d). In other embodiments,additional stepper motors (not shown) may be used to independentlyrotate each magnet. In yet another embodiment, all of the magnets 110are coupled to a single stepper motor (not shown). The stepper motors2834, 2836 may be controlled by a host computer or controller (such asthe controller 624 shown in FIG. 6) to coordinate the rotation of themagnets 110 at a desired frequency to generate a changing magnetic fieldsuitable for adjusting the annuloplasty ring 100.

The strength of the magnetic field generated by the magnets 110 in thearea between the first arm 2810 and the second arm 2812, and insurrounding areas, is based on the polar alignment (e.g., north andsouth poles) of each magnet 110. For example, FIGS. 29A, 29B, 29C, and29D schematically illustrate end views of the magnets 110 of theexternal magnetic adjustment device 102 shown in FIG. 28 according tocertain embodiments. In the illustrated examples, a first magnetic pole(e.g., north) is represented by a white semicircle and a second magneticpole (e.g., south) is represented by a black semicircle. The illustratedexamples also graphically illustrate the resulting magnetic field linesresulting from each polar alignment configuration.

In FIG. 29A, the magnets 110 are in an anti-aligned (Halbach)arrangement with the line separating the magnetic poles in each magnet110 set at a 0° offset from a horizontal direction. In this arrangement,the magnetic fields from each magnet 110 combine so as to augment thetotal magnetic field (as illustrated by the arrow 2910) in the centralarea of the magnet array, while reducing (or not augmenting) themagnetic field in areas outside of the magnet array. Thus, anannuloplasty ring located in the central area of the magnet array may beadjusted in a medical setting (e.g., in a hospital or physician'soffice) without the magnetic field altering nearby medical ornon-medical devices. When the magnets 110 are rotated in unison, themagnetic field in the central area of the magnet array rotates in theopposite direction. For example, FIG. 29B illustrates the magnets 110rotated 45° in a clockwise direction as compared to the arrangement ofFIG. 29A. Accordingly, the total magnetic field in the central area ofthe magnet array (as illustrated by the arrow 2912) is also rotated 45°,but in the counterclockwise direction.

In FIG. 29C, the magnets 110 are in an aligned arrangement such that themagnetic poles are all facing the same direction. Further, the lineseparating the magnetic poles in each magnet 110 set at a 0° offset froma horizontal direction. In this arrangement, the magnetic fields fromeach magnet 110 also combine so as to augment the total magnetic field(as illustrated by the arrow 2914) in the central area of the magnetarray. However, in some embodiments (see FIG. 30A), the total magneticfield generated in the central region by the aligned arrangement shownin FIG. 29C may not be as great as that of the Halbach arrangement shownin FIG. 29A. Further, the total magnetic field in central region of themagnet array may decrease as the magnets 110 are rotated. For example,FIG. 29D illustrates the magnets 110 rotated 45° in a clockwisedirection as compared to the arrangement of FIG. 29C. Accordingly, thetotal magnetic field in the central area of the magnet array (asillustrated by the arrow 2916) is also rotated 45° in the clockwisedirection. However, the magnitude of the total magnetic field in thecentral region of the magnet array is reduced due to counteractingmagnetic fields generated by the first magnet 110(a) and the fourthmagnet 110(d).

FIGS. 30A and 30B graphically represent example magnetic fieldmeasurements as the magnets 110 of the external magnetic adjustmentdevice 102 are rotated according to certain embodiments. FIG. 30Arepresents data corresponding to aligning 3 inch magnets 110 in a squarearrangement that is approximately 8.5 inches×8.5 inches. A first graph3010 (with data points represented by triangles) corresponds to aHalbach arrangement (see FIGS. 29A and 29B) with a gauss meter alignedat 0° with respect to the horizontal direction. A second graph 3012(with data points represented by squares) corresponds to the Halbacharrangement (see FIGS. 29A and 29B) with the gauss meter aligned at 45°with respect to the horizontal direction. A third graph 3014 (with datapoints represented by circles) corresponds to an aligned arrangement(see FIGS. 29C and 29D) with the gauss meter aligned at 0° with respectto the horizontal direction. A fourth graph 3016 (with data pointsrepresented by diamonds) corresponds to the aligned arrangement (seeFIGS. 29C and 29D) with the gauss meter aligned at 45° with respect tothe horizontal direction. As shown in FIG. 30A, the Halbach arrangementprovides stronger magnetic fields in the central region of the magnetarray, as compared to that of the aligned arrangement.

FIG. 30B represents data corresponding to aligning 3 inch magnets 110 ina rectangular arrangement that is approximately 8.5 inches×17 inches. Afirst graph 3018 (with data points represented by triangles) correspondsto a Halbach arrangement (see FIGS. 29A and 29B) with a gauss meteraligned at 0° with respect to the horizontal direction. A second graph3020 (with data points represented by squares) corresponds to theHalbach arrangement (see FIGS. 29A and 29B) with the gauss meter alignedat 90° with respect to the horizontal direction. A third graph 3022(with data points represented by circles) corresponds to an alignedarrangement (see FIGS. 29C and 29D) with the gauss meter aligned at 0°with respect to the horizontal direction. A fourth graph 3024 (with datapoints represented by diamonds) corresponds to the aligned arrangement(see FIGS. 29C and 29D) with the gauss meter aligned at 90° with respectto the horizontal direction. As shown in FIG. 30B, the differencesbetween the third graph 3022 and the fourth graph 3024 illustrate thatthe aligned arrangement does not produce a consistent magnetic field inthe central region of the magnet array as the magnets 110 are rotated.

FIG. 31 is a schematic diagram of an external magnetic adjustment device102 that includes two electromagnets 3110(a), 3110(b) according to oneembodiment. Using electromagnets 3110(a), 3110(b) allows the magneticfield generated by the external magnetic adjustment device 102 to beturned off when not in use. Further, in certain embodiments, theelectromagnets 3110(a), 3110(b) are driven to provide a constantabsolute value for the total magnetic field (as discussed below) as thedirection of the total magnetic field is rotated at a selectedfrequency. In addition, or in other embodiments, the electromagnets3110(a), 3110(b) may be electronically driven so as to selectivelyadjust the magnitude of the total magnetic field.

As shown in FIG. 31, the electromagnets 3110(a), 3110(b) according toone embodiment are C-shaped. The C-shape reduces or eliminates themagnitude of the magnetic field outside an area where a patient 106 isbeing treated. As illustrated by the magnetic field lines in FIG. 31,the magnetic field generated by each electromagnet 3110(a), 3110(b) isfairly well maintained between the opposite ends (e.g., a north “N” endand south “S” end) of the respective electromagnet 3110(a), 3110(b).Although not shown, each electromagnet 3110(a), 3110(b) may include, forexample, a ferromagnetic core (such as iron) wrapped with anelectrically conductive wire. In certain embodiments, the gap betweenthe ends of each C-shaped electromagnet 3110(a), 3110(b) is adjustable.For example, the respective backbones 3112(a), 3112(b) may each includea pivot or slide point.

A first electromagnet 3110(a) is positioned in a horizontal plane and asecond electromagnet 3110(b) is positioned in a vertical plane. Forexample, the “backbone” of the first electromagnet 3110(a) may be in thehorizontal plane with a patient table (not shown) and the “backbone”3112 of the second electromagnet 3112 may pass beneath the patienttable. All four magnet ends (two for each magnet 3110(a), 3110(b)) arepositioned in the horizontal plane. A patient 106 may be placed on thetable in an approximately 30° right-decubitus (right side downward)supine position on the table. In this position, the axis of the magnet108 in the annuloplasty ring 100 (not shown in FIG. 31) is approximatelyvertical, and the combined magnetic field is approximately centeredaround the patient's heart.

FIG. 32 graphically illustrates various parameters of the magneticfields generated by the external magnetic adjustment device 102 shown inFIG. 31 according to one embodiment. A first graph 3210 illustrates anX-direction component (e.g., that contributed by the magnet 3110(a)) ofthe combined magnetic field in arbitrary (normalized) units. A secondgraph 3212 illustrates a Y-direction component (e.g., that contributedby the magnet 3110(b)) of the combined magnetic field in arbitrary(normalized) units. As shown, the first graph 3210 and the second graph3212 are 90° out of phase from one another. By driving the X andY-directions of the magnetic fields in this manner, the absolute valueof the total field strength of the magnetic field is constant, asillustrated by a third graph 3214. A fourth graph 3216 (shown as adashed line) illustrates the direction of the total field in degrees. Astime progresses, the direction of the total field cycles between 0° and360° to turn the magnet 108 in the annuloplasty ring 100 implantedwithin the patient 106.

Example Magnetic Brake Embodiment

In certain embodiments, vibrations from a patient's beating heart maycause undesirable rotation of the magnet 108 and inadvertent adjustmentof the annuloplasty ring 100. Thus, in one embodiment, a magnetic brakeis implanted within a patient in an area outside of the patient's heart.For example, FIG. 33A is a schematic diagram of a superior section viewof a heart 104 illustrating an annuloplasty ring 100 implanted in theheart 104 and a magnetic brake assembly 3310 implanted outside of theheart 104 according to one embodiment. The annuloplasty ring 100 isattached to or near the mitral valve 107 annulus.

The magnetic brake assembly 3310 includes a housing 3312 and a brakemagnet 3316 coupled to bearings 3316 in the housing such that the brakemagnet 3314 may rotate therein. As discussed above with respect to theinternal magnet 108 of the annuloplasty ring 100 and the externalmagnets 110 of the magnetic adjustment device 102 (shown, e.g., in FIG.1B, FIG. 3, FIG. 4, FIG. 6, and FIG. 28), the brake magnet 3314 mayinclude a cylindrical magnet having magnetic poles divided along a planerunning the length of the cylinder. As shown in FIG. 33B, which is aschematic diagram illustrating an end view of the brake magnet 3314 andthe internal magnet 108 in the annuloplasty ring 100 shown in FIG. 33A,the magnetic field of the brake magnet 3314 interacts with the magneticfield of the internal magnet 108 of the annuloplasty ring 100 to preventrotation of either magnet 3314, 108. Thus, in the absence of theexternal magnetic field generated by the external adjustment device 102,the internal magnet 108 and the brake magnet 3314 are in “phase lock.”The annuloplasty ring 100 may still be adjusted when desired, however,because the external adjustment device 102 generates a sufficientlylarge rotating magnetic field to overcome the coupling between theinternal magnet 108 and the brake magnet 3314.

For example, FIGS. 34A and 34B schematically illustrate end views of thebrake magnet 3314 and the internal magnet 108 of the annuloplasty device100 according to one embodiment. In the illustrated examples, a firstmagnetic pole (e.g., north) is represented by a white semicircle and asecond magnetic pole (e.g., south) is represented by a black semicircle.In FIG. 34A, field lines 3410 corresponding to an external magneticfield are represented as having a lower density than field lines 3412shown in FIG. 34B. Thus, in the example of FIG. 34A the externalmagnetic field is relatively weak such that the magnetic poles of themagnets 3314, 108 may overcome the magnetic field to align with eachother. In the example of FIG. 34A, however, the external adjustmentdevice 102 may be activated to produce a relatively stronger externalmagnetic field that overcomes the attraction between the magnets 3314,108. Accordingly, both magnets 3314, 108 align their respective poleswith the strong external magnetic field. In other words, both theinternal magnet 108 of the annuloplasty ring 100 and the brake magnet3314 are rotated during selective adjustment of the annuloplasty ring'ssize.

It will be understood by those having skill in the art that many changesmay be made to the details of the above-described embodiments withoutdeparting from the underlying principles of the invention. The scope ofthe present invention should, therefore, be determined only by thefollowing claims.

The invention claimed is:
 1. A system for changing the dimension of aportion of a subject comprising: an adjustable implant configured forimplantation within a patient comprising: a tubular member; an internalmagnet disposed within the tubular member, the internal magnetconfigured to rotate in response to a moving magnetic field originatingexternal to the subject; an adjustable member operatively coupled to theinternal magnet, wherein the internal magnet is configured to rotate inresponse to the moving magnetic field and change a dimension of theadjustable implant as the internal magnet rotates; and a magnetic brakeconfigured for implantation within a patient, wherein, in the absence ofthe moving magnetic field, the magnetic brake is configured to preventthe internal magnet from rotating, and wherein, in the presence of themoving magnetic field, the magnetic brake is configured to allow theinternal magnet to rotate.
 2. The system of claim 1, wherein theadjustable implant is an adjustable annuloplasty ring.
 3. The system ofclaim 1, wherein the internal magnet comprises a cylindrical magnethaving magnetic poles divided along a plane running the length of thecylinder.
 4. The system of claim 3, wherein the internal magnet is apermanent magnet.
 5. The system of claim 1, wherein the adjustableimplant further comprises: a lead screw coupled to a first end of theinternal magnet, wherein the lead screw rotates with the rotatinginternal magnet; and a drive nut coupled to the adjustable member,wherein threads of the drive nut engage threads of the lead screw, andwherein rotation of the lead screw through the drive nut pulls or pushesthe adjustable member.
 6. The system of claim 1, further comprising: anexternal adjustment device comprising one or more external magnetsconfigured to generate the moving magnetic field.
 7. The system of claim6, wherein the external adjustment device further comprises: acontroller; and a first stepper motor in communication with thecontroller, the first stepper motor coupled to at least a first subsetof the one or more external magnets, wherein the controller isconfigured to control the rotation of the first stepper motor.
 8. Thesystem of claim 7, wherein the one or more external magnets comprisefour cylindrical magnets in a non-aligned, Halbach configuration.
 9. Thesystem of claim 6, wherein the one or more external magnets comprise twoC-shaped electromagnets arranged to generate respective magnetic fieldsthat are perpendicular to one another.
 10. The system of claim 6,wherein the one or more external magnets comprise an electromagnet.